In a communications system, channel encoding is usually performed to improve data transmission reliability and ensure communication quality. A polar code is an encoding manner that can achieve a Shannon capacity and has low coding-decoding complexity. The polar code is a linear block code, including one or more information bits and one or more frozen bits. A generator matrix of the polar code is GN, and an encoding process of the polar code is X1N=u1NGN, where u1N={u1, u2, . . . , uN} is a binary row vector with a length of N.